Sensors that can link to other sensors and computer systems continue to be embedded with more and more devices or objects, resulting in the “internet of everything” (also referred to as the “internet of things”), using a variety of wired and/or wireless communication technologies. The growth in connectivity results in machine-to-machine (M2M) or device-to-device (D2D) communications without the need for human intervention. Some examples of integration include devices that integrate sensors or meters to capture information that is then relayed to a remote system, such as a central server. This can include smart metering, temperature monitoring, pressure monitoring, fluid flow monitoring, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, transaction-based business charging, and other applications.
Given their nature, these IoE devices are typically designed to consume low amounts of power and have low cost. For example, a sensor deployed in a gas meter (resulting in a “smart meter”) may be expected to last years without replacement or recharge (if recharging is possible). In contrast, a UE, such as a mobile device, has significantly more transmit power that, together with other features of the given UE, consume enough power that the UE is expected to be recharged every few days, if not daily or more frequently.
IoE devices are designed to periodically wake up to deliver their data to a central server or other device(s). In various media access control (MAC) protocols, it is desirable to have the IoE devices in a particular geographic area be time synchronized. In this regard, it is easier to establish mesh routing and efficient MAC scheduling among synchronized IoE devices than among asynchronous IoE devices. As a result, there is a need for techniques to improve the synchronization of IoE devices that also limit the amount of IoE device power required.